Add or remove GST in one tap
Most calculators only do one direction. Both flows live here behind a single toggle, so a quick invoice check and a back-calculation use the same interface.
GST Calculator
Add or remove GST from any amount and see the CGST, SGST, and IGST split instantly. Built for Indian rates (3%, 5%, 12%, 18%, 28%) with presets for Australia, Canada, Singapore, New Zealand, and the UK.
Guide
How to use the GST calculator
1
Pick a direction
Choose Add GST if your amount is the base price and you want to know the final total. Choose Remove GST if your amount already includes tax and you want to extract the base.
2
Enter the amount
Type your number in the amount field. Pick the currency on the left of the input if you need anything other than INR. The currency change also seeds the default rate for that country.
3
Set the GST rate
Click one of the preset rates (3%, 5%, 12%, 18%, 28%) or type a custom percent in the field below. The result table re-calculates the moment you change anything.
4
Read or copy the result
The table shows base, GST amount, and total. The breakdown cards show CGST (half rate), SGST (half rate), and IGST (full rate). Click Copy summary to send a plain-text receipt to your clipboard.
What this calculator does
GST (Goods and Services Tax) is the indirect tax most countries charge on a sale. The math is simple once you know which direction to apply it. Adding GST takes a base price and gives you the tax plus the final invoice amount. Removing GST takes an invoice total that already includes tax and gives you the base price and how much tax was inside.
This calculator does both, live. Pick Add or Remove at the top, type your amount, pick a GST rate (or set a custom percent). The result table shows the base, the GST amount, and the total. Below that, India’s CGST/SGST/IGST breakdown shows how the same GST splits across intra-state and inter-state sales.
Default presets cover the five Indian slabs (3%, 5%, 12%, 18%, 28%) and country presets for Australia (10%), Canada (5%), Singapore (9%), New Zealand (15%), and the UK (20%). For everything else, the custom rate field accepts any percent. The numbers update as you type. Nothing is sent to a server.
Benefits
Why use this GST calculator
CGST, SGST, and IGST breakdown
Same GST, two views. The split shows CGST and SGST at half the rate each (intra-state sales) and IGST at the full rate (inter-state sales).
All five Indian GST slabs preset
One-click presets for 3%, 5%, 12%, 18%, and 28%, the five slabs the GST Council uses. The custom field still accepts decimals for special rates.
Six currencies, sensible defaults
Switch the currency to AUD, CAD, SGD, NZD, or GBP and the default GST rate updates to match the country (10%, 5%, 9%, 15%, 20%). INR is the default.
Live result, no calculate button
The numbers re-compute as you type the amount or change the rate. No button to click, no waiting on a round trip.
Copy a clean text summary
The Copy summary button puts a 7-line plain-text receipt on your clipboard with base, GST, total, and the CGST/SGST/IGST split, ready to paste into an email, note, or invoice.
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FAQ
Frequently Asked Questions
Quick answers about GST math, the CGST/SGST/IGST split, and what this calculator does.
How is GST calculated when you add it to a price?
The GST amount is the base price multiplied by the rate divided by 100. The total is the base plus that GST amount. For an ₹1,000 product at 18% GST, the GST is ₹180 and the total is ₹1,180.
How do I extract GST from an inclusive total?
Use the formula base = total × 100 / (100 + rate). For ₹1,180 incl. 18% GST, the base is ₹1,000 and the GST inside is ₹180. The Remove GST mode in the calculator does this automatically.
What is the difference between CGST, SGST, and IGST?
CGST and SGST apply to intra-state sales (buyer and seller in the same Indian state) and split the GST evenly between the central and state governments. IGST applies to inter-state sales and is charged at the full GST rate by the central government. The total tax collected is the same in both cases.
Which GST rate should I pick?
India uses five slabs: 3% for gold and precious metals, 5% for essential goods and many food items, 12% for processed food and standard goods, 18% for most services and electronics, and 28% for luxury items. Check the official GST Council schedule when in doubt.
Does this calculator handle currencies other than INR?
Yes. Switch the currency dropdown to AUD, CAD, SGD, NZD, GBP, or Other. The math works the same way for any flat-rate sales tax. The CGST/SGST/IGST labels are an India convention but the underlying half-rate split is shown for any rate.
Are my amounts sent anywhere?
No. The calculation runs in JavaScript inside your browser tab. No upload, no signup, no analytics on the amounts you type. Open the dev tools network panel during use and you will see zero outbound requests.
How accurate are the results?
The math uses standard double-precision floating point and rounds the display to two decimal places. For invoice-level accounting that needs exact rupee arithmetic, double-check the totals with your billing software before filing.